Group III elements include Al, Ga and In; Group IV elements include C, Si and Ge; Group V elements include P, As and Sb. For Group III-V based optoelectronics such as lasers, LEDs and PDs, on Group IV (e.g., Si) substrates relatively thick layers (e.g., >1 μm) of Group III-V material are needed to compensate for the typically high defect density at the interface of Group IV and Group V material systems. It can be disadvantageous both time-wise and expense-wise to epitaxially deposit such relatively thick layers.